New NOAA-led report
examines climate conditions experienced around the world

July 10,
2012

Worldwide, 2011 was the
coolest year on record since 2008, yet temperatures remained above the 30
year average, according to the 2011 State of the Climate report
released
online
today by NOAA. The peer-reviewed report, issued in coordination with the
American Meteorological Society (AMS), was compiled by 378 scientists from
48 countries around the world. It provides a detailed update on global
climate indicators, notable weather events and other data collected by
environmental monitoring stations and instruments on land, sea, ice and
sky.

“2011 will be remembered as
a year of extreme events, both in the United States and around the world,”
said Deputy NOAA Administrator Kathryn D. Sullivan, Ph.D. “Every weather
event that happens now takes place in the context of a changing global
environment. This annual report provides scientists and citizens alike
with an analysis of what has happened so we can all prepare for what is to
come.”

Two back-to-back La Niñas,
each characterized by cooler-than-average water temperatures in the
eastern equatorial Pacific, affected regional climates and influenced many
of the world’s
significant weather events throughout the year. These included
historic droughts in East Africa, the southern United States and northern
Mexico. La Niña conditions contributed to an above-average tropical
cyclone season in the North Atlantic hurricane basin and a below-average
season in the Eastern North Pacific. It was also associated with the
wettest two-year period (2010–2011) on record in Australia, which was
particularly remarkable as the wet conditions followed a decade-long dry
spell.

The lead character of the
2011 climate story was a double dip La Niña, which chilled the Pacific at
the start and end of the year. Many of the 2011 seasonal climate patterns
around the world were consistent with common side effects of La Niña

The Arctic continued to
show more rapid changes than the rest of the planet. Sea ice shrank to its
second smallest “summer minimum” extent on record during 2011, as older
ice (four to five years old) reached a new record minimum at more than 80
percent below average. Overall, glaciers around the world continued to
lose mass. Loss from Canadian Arctic glaciers and ice caps were the
greatest since measurements began in 2002.

Warm temperature
trends continue: Four independent datasets show 2011 among the
15 warmest since records began in the late 19th century, with
annually-averaged temperatures above the 1981–2010 average, but coolest
on record since 2008. The Arctic continued to warm at about twice the
rate compared with lower latitudes. On the opposite pole, the South Pole
station recorded its all-time highest temperature of 9.9°F on December
25, breaking the previous record by more than 2 degrees.

Greenhouse gases
climb: Major greenhouse gas concentrations, including carbon
dioxide, methane, and nitrous oxide, continued to rise. Carbon dioxide
steadily increased in 2011 and the yearly global average exceeded 390
parts per million (ppm) for the first time since instrumental records
began. This represents an increase of 2.10 ppm compared with the
previous year. There is no evidence that natural emissions of methane in
the Arctic have increased significantly during the last decade.

Arctic sea ice
extent decreases: Arctic sea ice extent was below average for
all of 2011 and has been since June 2001, a span of 127 consecutive
months through December 2011. Both the maximum ice extent (5.65 million
square miles, March 7) and minimum extent (1.67 million square miles,
September 9) were the second smallest of the satellite era.

Ozone levels in
Arctic drop: In the upper atmosphere, temperatures in the
tropical stratosphere were higher than average while temperatures in the
polar stratosphere were lower than average during the early 2011 winter
months. This led to the lowest ozone concentrations in the lower Arctic
stratosphere since records began in 1979 with more than 80 percent of
the ozone between 11 and 12 miles altitude destroyed by late March,
increasing UV radiation levels at the surface.

Sea surface
temperature & ocean heat content rise: Even with La Niña
conditions occurring during most of the year, the 2011 global sea
surface temperature was among the 12 highest years on record. Ocean heat
content, measured from the surface to 2,300 feet deep, continued to rise
since records began in 1993 and was record high.

Ocean salinity
trends continue: Continuing a trend that began in 2004 and
similar to 2010, oceans were saltier than average in areas of high
evaporation, including the western and central tropical Pacific, and
fresher than average in areas of high precipitation, including the
eastern tropical South Pacific, suggesting that precipitation is
increasing in already rainy areas and evaporation is intensifying in
drier locations.

The report also
provides details on a number of extreme events experienced all over
the globe, including the worst flooding in Thailand in almost 70
years, drought and deadly tornado outbreaks in the United States,
devastating flooding in Brazil and the worst summer heat wave in
central and southern Europe since 2003.

The 2011 State of
the Climate report is peer-reviewed and published annually as a
special supplement to the Bulletin of the American Meteorological
Society. The report is part of a suite of climate services NOAA
provides government, business and community leaders so they can make
informed decisions. It was edited by Jessica Blunden, Ph.D., and Deke
Arndt of NOAA’s National Climatic Data Center.

Additionally, for the
first time a complementary article has been published by AMS today
examining the linkages between climate change and extreme events of
2011. The paper looks at six global extreme weather and climate events
from last year.

Findings:

Determining the
causes of extreme events remains difficult. While scientists cannot
trace specific events to climate change with absolute certainty, new
and continued research help scientists understand how the
probability of extreme events change in response to global warming.

La Niña-related heat
waves, like that experienced in Texas in 2011, are now 20 times more
likely to occur during La Niña years today than La Niña years fifty
years ago.

The UK experienced a
very warm November 2011 and a very cold December 2010. In analyzing
these two very different events, UK scientists uncovered interesting
changes in the odds. Cold Decembers are now half as likely to occur
now versus fifty years ago, whereas warm Novembers are now 62 times
more likely.

Climate change
cannot be shown to have played any role in the 2011 floods on the
Chao Phraya River that flooded Bangkok, Thailand. Although the
flooding was unprecedented, the amount of rain that fell in the
river “catchment” area was not very unusual. Other factors, such as
changes in reservoir policies and increased construction on the
flood plain, were found most relevant in setting the scale of the
disaster.

The paper,
Explaining Extreme Events of 2011 from a Climate Perspective, was
produced by NOAA and UK Met Offices scientists as well as numerous
colleagues around the world. It was edited by Thomas Peterson, NOAA’s
National Climatic Data Center; Peter Stott, UK Met Office-Hadley
Center; and Stephanie Herring, NOAA’sOffice of
Program Planning and Integration. The
study
can be viewed online.

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Global Highlights

This year tied 1997 as the
11th warmest year since records began in 1880. The annual
global combined land and ocean surface temperature was 0.51°C (0.92°F)
above the 20th century average of 13.9°C (57.0°F). This marks the 35th
consecutive year, since 1976, that the yearly global temperature was
above average. The warmest years on record were 2010 and 2005, which
were 0.64°C (1.15°F) above average.

Separately, the 2011 global
average land surface temperature was 0.8°C (1.49°F) above the 20th
century average of 8.5°C (47.3°F) and ranked as the eighth warmest on
record. The 2011 global average ocean temperature was 0.40°C (0.72°F)
above the 20th century average of 16.1°C (60.9°F) and ranked
as the 11th warmest on record.

La Niña, which is defined
by cooler-than-normal waters in the eastern and central equatorial
Pacific Ocean that affects weather patterns around the globe, was
present during much of 2011. A relatively strong phase of La Niña opened
the year, then dissipated in the spring before re-emerging in October
and lasting through the end of the year. When compared to previous La
Niña years, the 2011 global surface temperature was the warmest observed
during such a year.

The 2011 globally-averaged
precipitation over land was the second wettest year on record, behind
2010. Precipitation varied greatly across the globe. La Niña contributed
to severe drought in the Horn of Africa and to Australia's third wettest
year in its 112-year period of record.

Global Temperatures

The year 2011 tied with 1997 as the 11th
warmest year since records began in 1880. The annually-averaged
temperature over global land and ocean surfaces was 0.51°C (0.92°F) above
the 20th century average of 13.9°C (57.0°F). This marks the 35th
consecutive year (since 1976) that the yearly global temperature was above
the 20th century average. The warmest years on record were 2010
and 2005, which were 0.64°C (1.15°F) above average. Including 2011, all
eleven years in the 21st century so far (2001–2011) rank among
the 13 warmest in the 132-year period of record. Only one year during the
20th century, 1998, was warmer than 2011.

Natural climate patterns that persist for
days, months, or even years can affect weather patterns around the world
and impact the average global temperature. One such well-known
global-scale pattern—the El Niño-Southern Oscillation (ENSO)—is a natural
episodic fluctuation in sea surface temperature (El Niño) and the air
pressure of the overlying atmosphere (Southern Oscillation) across the
equatorial Pacific Ocean. Over a period of months to a few years, ENSO
fluctuates between warmer-than-average ocean surface waters (El Niño) and
cooler-than-average ocean surface waters (La Niña) in that region.

Two separate cool-phase La Niña events took
place in 2011, according to NOAA's Climate Prediction Center (CPC). These
events affected weather patterns in many parts of the world during the
year and dampened the global temperature compared with the record warmth
of the previous year, 2010 (which is tied for warmest with 2005). The
coolest monthly global anomalies occurred during the beginning of the
year, where both January and February each ranked as 17th warmest for
their respective months. Monthly temperature anomalies increased as the La
Niña episode waned and ENSO-neutral conditions emerged during May. June
and July ranked as the seventh warmest for their respective months while
August and September each ranked eighth warmest. La Niña conditions
returned in October and moderately strengthened during the remainder of
the year. Global monthly temperature anomalies during this period cooled
compared to those during the middle of the year.

With CPC ENSO records dating back to 1950,
2011 ranked as the warmest "La Niña year" in the 1950–2011 period of
record. Two of the three warmest years on record (2010 and 1998) are "El
Niño years". A La Niña (El Niño) year is defined here as occurring when
the first three months of a calendar year meet the La Niña (El Niño)
criteria as defined by the CPC.

Global Annual Temperature
Anomalies

Separately, the average global land
temperature was 0.83°C (1.49°F) above the 20th century average and ranked
as the eighth warmest year on record. It was also the warmest annual
global temperature over land during a La Niña year. The average monthly
land temperature anomaly ranged from 0.45°C (0.81°F; January) to 1.12°C
(2.02°F; April), a difference of 0.67°C (1.21°F).

Already well into the La Niña phase that began in mid-2010, the
globally-averaged January ocean surface temperature was the 11th warmest
January on record, but the warmest among all Januaries when La Niña was
present. The ten warmest Januaries occurred during either El Niño or
ENSO-neutral conditions. During the year, the global monthly ocean
temperature anomaly ranged between 0.32°C (0.58°F; December) and 0.47°C
(0.85°F; July), a difference of 0.15°C (0.27°F). For the period
January–December, the ENSO-neutral conditions that were sandwiched by La
Niña events at the beginning and end of 2011 contributed to a globally
averaged ocean surface temperature anomaly of 0.40°C (0.72°F) above the
20th century average, the 11th warmest year on record. It was also the
warmest global ocean temperature anomaly among all La Niña years. 2003 and
1998— both El Niño years—tie for the warmest years on record, at 0.51°C
(0.92°F) above average.

Regional Temperatures

Warmer-than-average temperatures occurred during 2011 for most of the
world's surface. The greatest above-average annual temperature anomalies
occurred across the Northern Hemisphere high latitude land areas,
particularly central and northern Russia, Scandinavia, and Canada. Also
noteworthy, it was warmer than average across the eastern half of the
United States, Mexico, most of Europe and Africa, and the north central
Pacific Ocean. Temperatures were below normal across the eastern and
central Pacific Ocean, west central North America, and north and central
Australia.

A natural hemispheric-scale climate pattern
called the Arctic Oscillation (AO) can be a dominating driver of winter
temperatures in the Northern Hemisphere. Its effects were particularly
felt during January, when the AO was strongly negative. A negative AO is
associated with cold polar air that spills southward into the
mid-latitudes from the Arctic region and warm air that advects northward.

Due at least in part to this pattern, the
contiguous United States reported its coolest January since 1994. December
2010 was also slightly below average, helping to bring the United States
its second cooler-than-normal winter (December–February) in a row. In
China, 2011 was also off to a cold start. It was the coolest January,
behind 1977, since records began in 1961. In Europe, the UK reported its
second coolest winter (behind 2009/10) since 1985/86.

Conversely, in the higher northern
latitudes, Canada reported its sixth warmest winter since national records
began in 1948. The warmest winter occurred the previous year (2009/10).
Most of the above-normal temperatures occurred in the northern half of the
country. Temperatures were more than 4°C (7°F) above normal for large
areas of Nunavut, northern Quebec, and Labrador. The negative-phase AO
contributed to these warm northern temperatures.

In the Southern Hemisphere, the summer
(December 2010–February 2011) was Australia's coolest since 2001. These
cooler temperatures can be attributed in part to the ongoing La Niña
event. Cool conditions, in association with increased cloudiness and
above-average rainfall, continued across Australia into March as
nationally-averaged March daytime temperatures ranked as the coolest March
on record. With cool conditions persisting into April and May, Australia
had its coolest autumn (March–May) on record.

Parts of Western Europe reported record or
near-record warmth during April. Germany experienced its second warmest
April since national records began in 1881, behind April 2009, with the
average nationwide temperature almost 4.4°C (7.9°F) above average. It was
the warmest April on record across the United Kingdom, with temperatures
3°C to 5°C (5°F to 9°F) above normal in many areas, breaking the previous
record set in 2007 by 0.5°C (0.9°F). This warmth also contributed to the
UK's warmest spring on record (tied with 2007).

Spain experienced its third warmest May on
record, behind 1964 and 2006. But in Australia, the effects of La Niña
continued. Cool weather brought the country its seventh coolest May on
record and it's coolest May since 2000, at 1.33°C (2.39°F) below averageIn
contrast to Australia, New Zealand reported its warmest May since records
began in 1909, with the temperature 2.2°C (4.0°F) above the monthly
average. New Zealand also had its third warmest June on record, with the
temperature 1.5°C (2.7°F) above the monthly average. .

Summer was warm across China. June 2011 was
the second warmest June for the country since records began in 1951, July
was the seventh warmest, and August was the fourth warmest on record.

In July, with ENSO-neutral conditions in
place, maximum temperatures were above normal for all states and
territories in Australia for the first month since April 2010. La Niña
conditions during 2010/11 kept temperatures below normal across most of
the country for more than a year.

The UK had its coolest average monthly July
temperature since 2000. The average minimum temperature was the coolest
since July 1980. Spain had its coolest July since 2002, although the
temperature was only 0.1°C (0.2°F) below the 1971–2000 average. The
cooler-than-average temperatures continued into August in some regions.
Scotland and Northern Ireland had their coolest average monthly August
temperatures since 1993.

In North America, a major heat wave
contributed to the third warmest July on record for the United States.
This warmth was followed by more heat, particularly in the South, giving
the U.S. its second warmest August. The warmth in the United States during
July and August contributed to the country's second warmest summer. Two
states, Oklahoma and Texas, reported the highest U.S. summer temperatures
for any state in any year since records began in 1895.

In Northern Europe, Finland had its fourth
warmest summer since records began in the early 1900s. In Iberia, Spain
rebounded from its cool July and reported its sixth warmest August on
record since 1961. In the Southern Hemisphere, Australia had its fifth
warmest August maximum temperature in the 62-year period of record.

As Northern Hemisphere fall
(September–November) began, it was the warmest September in Spain since
1990 and fifth warmest in the past 50 years. The UK marked its warmest
September since 2006 and sixth warmest in the last 100 years. It also
reported its warmest October since 2006 and eighth warmest in the last 100
years. However, most of southern and western South America was cooler than
average. According to the Argentina Meteorological Service (Servicio
Meteorologico Nacional), several locations in Argentina experienced their
coolest October in the past half century.

In Asia, China reported its sixth warmest
October and third warmest November since national records began in 1951.

The November average monthly temperature in
Norway was 4.6°C (8.3°F) above average, making this month the country's
warmest November since records began in 1900. The average temperature for
Northern Norway was 5.3°C (9.5°F) above normal, also a new November
record. These warm temperatures helped give Norway its warmest autumn on
record. It was also Finland's warmest autumn since 1938.

The average November temperature for
Austria's high elevation stations was 2.6°C above average, giving this
region the second warmest November in the country's 161-year period of
record, behind 2006.

November 2011 was the second warmest
November on record for the UK, behind 1994, at 2.9°C (5.2°F) above normal.
It was also the second warmest autumn on record for the UK in more than a
century, with temperatures 2.1°C (3.8°F) above average. November 2006 was
the warmest at 2.3°C (4.1°F) above average. In Central England, autumn
temperatures were the second warmest in at least 350 years.

In December, a strong positive Arctic
Oscillation kept polar air contained to the very high northern latitudes
and much warmer-than-normal temperatures were observed in lower, but still
high, northern latitudes. Alaska reported its third warmest December on
record and Northern Norway had its 10th warmest December in the 112-year
period of record. In Europe, the UK had its sixth warmest December on
record. This is more than 5°C (9°F) warmer than the record cold of the
previous December (2010), when the Arctic Oscillation was strongly
negative.

Australia temperatures were plagued by the
La Niña that emerged in October. It was the country's coolest December
since 2001.

For the year, in Northern Europe, the 2011
annually-averaged temperature for Norway was 1.8°C above average, tying
with 1990 and 2006 as the country's warmest year on record. Finland tied
with 1989 for its second warmest year on record, behind 1938, with
March–December all warmer-than-average months. According to the Finnish
Meteorological Institute, the average temperature for 2011 was 1.9°C
(3.4°F) above the long-term average.

In Southern Europe, it was the warmest year
on record for Spain, at 1.49°C above the 1971–2000 average.

In Western Europe, the UK reported its
second warmest year on record, behind 2006. The UK Met Office also
reported that the UK's seven warmest years have all occurred within the
past decade.

Germany reported its fifth warmest year on
record, with all months except July warmer than average. The
annually-averaged temperature was 0.7°C above the 1981–2010 average.

For Austria's high elevation alpine
stations, the average temperature was the warmest since records began in
1851, at 1.6°C above the 1971–2000 average, according to ZAMG. This
surpassed the previous record set in 1994 by 0.3°C. The average
temperature for the country's low elevation stations ranked as sixth
warmest on record, at 1.2°C above average.

In the Southern Hemisphere, Australia
experienced its first cooler-than-average year since 2001, due in part to
the impacts of La Niña during most of 2011.

New Zealand, which experienced a year of
extreme weather, both hot and cold, observed an annually-averaged
temperature that was 17th warmest since records began in 1919, or warmer
than about 80 percent of all years, according to NIWA.

Global Precipitation

Global
precipitation over land in 2011 was well above the 1961–1990 average for
the second year in a row, ranking as the second wettest year on record,
behind 2010. Precipitation anomalies were variable across the globe. It
was wetter than normal across much of the northeastern United States,
Central America, much of coastal South America, Australia, and
northwestern China. It was particularly drier than normal in far
southwestern Canada, the south central United States, northern Mexico,
southern and northeastern China, Mongolia, Hawaii, and French Polynesia
and Kiribati in the South Pacific Ocean.

La Niña conditions during much of 2011
brought plenty of precipitation to Australia, making 2011 the country's
third wettest year since records began in 1900. The Australian Bureau of
Meteorology also attributed a record warm eastern Indian Ocean to the
extreme wetness. It was particularly wet at the beginning of 2011, as the
country reported its second wettest summer (December 2010–February 2011)
and wettest March on record. On a longer time scale, the two-year period
2010–2011 ranked as the second wettest such period on record.

However, in East Africa, two consecutive
seasons of poor rainfall—the short Deyr rains from October to December and
the long Gu rains that typically begin in early April but were late and
scattered—resulted in one of the driest years since 1950/51, according to
the UN's Office for the Coordination of Humanitarian Affairs (OCHA).
Somalia, Ethiopia, Eritrea, Kenya, and Djibouti were majorly impacted. The
lack of Deyr rains in October–December 2010 was attributed to the ongoing
La Niña. On July 19th, the United Nations offically declared a famine in
the southern Bakool and Lower Shabelle regions of Somalia, the first time
famine has been declared in this country since 1992. Please see the July
2011 Global Hazards report for detailed information.

La Niña also played a role in the intense
drought observed in northern Mexico and the south central United States.
As of the end of November, Mexico was suffering from its worst drought
since national records began in 1941. Five states in northern
Mexico—Durango, Zacatecas, Chihuahua, Coahuila and San Luis Potosi—were
the hardest hit. On average those states had received less than 60 percent
of average rainfall for that time period. Devastating drought conditions
were seen across much of the southern tier of the United States. Texas,
Oklahoma, Louisiana, and New Mexico were particularly hard hit and
billions of dollars in economic losses were incurred. Please see the
annual U.S. and Drought reports for details.

While some parts the U.S. were extremely
dry, other parts were record or near-record wet. Two major tropical storm
systems, Hurricane Irene and Tropical Storm Lee, each brought heavy
rainfall to much of the northeastern U.S. within about a one-week period
during late August and early September, respectively. These systems
contributed to several states, including heavily populated New York,
reporting their wettest years on record. Please see the U.S. annual report
for detailed precipitation information.

In October, two separate storm systems—a
tropical depression from the Pacific and another system from the
Caribbean—dumped nearly five feet (1520 mm) of rain in some areas across
Central America from the 10th to the 20th. Honduras, Costa Rica,
Guatemala, El Salvador, and Nicaragua were majorly impacted. Please see
the October Global Hazards report for detailed precipitation information.

In India, rainfall during the Southwest
Monsoon season (June–September) was near normal, at one percent above the
long-term average for the country as a whole. According to the India
Meteorological Department, precipitation ranged from 14 percent below
normal in the northeast of the country to 10 percent above normal in
Central India.

Conversely, Sindh Province in southern
Pakistan had its wettest monsoon season on record, with three and a half
times its average rainfall. Most of the rain fell in a four-week period
from mid-August to early-September.

The East Asian Monsoon brought heavy
precipitation to South Korea in 2011. The country had its wettest summer
on record, according to the World Meteorological Agency (WMO). On July
27th, the capital city of Seoul, South Korea experienced its heaviest
single-day rainfall (11.8 inches; 300 mm) since 1907.

Storms and heavy monsoon rains from late
July to November contributed to the worst flooding in Thailand since 1942.
Some areas were under six feet (two meters) of water. Other countries in
Southeast Asia were affected by the heavy rainfall, including Cambodia,
Myanmar, and Vietnam. Please see the November Global Hazards report for
detailed precipitation information.

The WMO reported that, in Europe, both
France and the Netherlands each had their driest spring on record. The
Netherlands followed with its wettest summer on record.

Austria's precipitation was 15 percent
below the 1971–2000 average, making this the driest year since 2003.
Contributing to this dryness was November, which was Austria's all-time
driest month on record.

In contrast, Norway reported its wettest
year, with records dating back to 1900. According to Meteorologisk
Institutt, on average, the country received 130 percent of average
rainfall, breaking the previous record of 125 percent set in 1983.

Annual precipitation varied greatly across
the UK. The UK Met Office reported that Scotland had its wettest year on
record, at 122.2 percent of average, while it was the second and third
driest years on record for East Anglia and the Midlands, respectively.

Credit:NOAA National Climatic Data Center, State of the
Climate: Global Analysis for Annual 2011,

Data compiled from The
British Antarctic Study, NASA, Environment Canada, UNEP, EPA and
other sources as stated and credited Researched by Charles
Welch-Updated daily This Website is a project of the The Ozooe Hole
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